<?php

    /**
     * PHPExcel_CachedObjectStorage_SQLite3
     * Copyright (c) 2006 - 2015 PHPExcel
     * This library is free software; you can redistribute it and/or
     * modify it under the terms of the GNU Lesser General Public
     * License as published by the Free Software Foundation; either
     * version 2.1 of the License, or (at your option) any later version.
     * This library is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     * Lesser General Public License for more details.
     * You should have received a copy of the GNU Lesser General Public
     * License along with this library; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     * @category   PHPExcel
     * @package    PHPExcel_CachedObjectStorage
     * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
     * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
     * @version    ##VERSION##, ##DATE##
     */
    class PHPExcel_CachedObjectStorage_SQLite3 extends PHPExcel_CachedObjectStorage_CacheBase implements PHPExcel_CachedObjectStorage_ICache {
        /**
         * Database table name
         * @var string
         */
        private $TableName = null;
        /**
         * Database handle
         * @var resource
         */
        private $DBHandle = null;
        /**
         * Prepared statement for a SQLite3 select query
         * @var SQLite3Stmt
         */
        private $selectQuery;
        /**
         * Prepared statement for a SQLite3 insert query
         * @var SQLite3Stmt
         */
        private $insertQuery;
        /**
         * Prepared statement for a SQLite3 update query
         * @var SQLite3Stmt
         */
        private $updateQuery;
        /**
         * Prepared statement for a SQLite3 delete query
         * @var SQLite3Stmt
         */
        private $deleteQuery;

        /**
         * Initialise this new cell collection
         * @param    PHPExcel_Worksheet $parent The worksheet for this cell collection
         */
        public function __construct(PHPExcel_Worksheet $parent) {
            parent::__construct($parent);
            if (is_null($this->DBHandle)) {
                $this->TableName = str_replace('.', '_', $this->getUniqueID());
                $_DBName         = ':memory:';
                $this->DBHandle = new SQLite3($_DBName);
                if ($this->DBHandle === false) {
                    throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
                }
                if (!$this->DBHandle->exec('CREATE TABLE kvp_' . $this->TableName . ' (id VARCHAR(12) PRIMARY KEY, value BLOB)')) {
                    throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
                }
            }
            $this->selectQuery = $this->DBHandle->prepare("SELECT value FROM kvp_" . $this->TableName . " WHERE id = :id");
            $this->insertQuery = $this->DBHandle->prepare("INSERT OR REPLACE INTO kvp_" . $this->TableName . " VALUES(:id,:data)");
            $this->updateQuery = $this->DBHandle->prepare("UPDATE kvp_" . $this->TableName . " SET id=:toId WHERE id=:fromId");
            $this->deleteQuery = $this->DBHandle->prepare("DELETE FROM kvp_" . $this->TableName . " WHERE id = :id");
        }

        /**
         * Identify whether the caching method is currently available
         * Some methods are dependent on the availability of certain extensions being enabled in the PHP build
         * @return    boolean
         */
        public static function cacheMethodIsAvailable() {
            if (!class_exists('SQLite3', false)) {
                return false;
            }
            return true;
        }

        /**
         * Add or Update a cell in cache identified by coordinate address
         * @param    string        $pCoord Coordinate address of the cell to update
         * @param    PHPExcel_Cell $cell   Cell to update
         * @return    PHPExcel_Cell
         * @throws    PHPExcel_Exception
         */
        public function addCacheData($pCoord, PHPExcel_Cell $cell) {
            if (($pCoord !== $this->currentObjectID) && ($this->currentObjectID !== null)) {
                $this->storeData();
            }
            $this->currentObjectID    = $pCoord;
            $this->currentObject      = $cell;
            $this->currentCellIsDirty = true;
            return $cell;
        }

        /**
         * Store cell data in cache for the current cell object if it's "dirty",
         *     and the 'nullify' the current cell object
         * @return    void
         * @throws    PHPExcel_Exception
         */
        protected function storeData() {
            if ($this->currentCellIsDirty && !empty($this->currentObjectID)) {
                $this->currentObject->detach();
                $this->insertQuery->bindValue('id', $this->currentObjectID, SQLITE3_TEXT);
                $this->insertQuery->bindValue('data', serialize($this->currentObject), SQLITE3_BLOB);
                $result = $this->insertQuery->execute();
                if ($result === false) {
                    throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
                }
                $this->currentCellIsDirty = false;
            }
            $this->currentObjectID = $this->currentObject = null;
        }

        /**
         * Get cell at a specific coordinate
         * @param     string $pCoord Coordinate of the cell
         * @throws     PHPExcel_Exception
         * @return     PHPExcel_Cell     Cell that was found, or null if not found
         */
        public function getCacheData($pCoord) {
            if ($pCoord === $this->currentObjectID) {
                return $this->currentObject;
            }
            $this->storeData();
            $this->selectQuery->bindValue('id', $pCoord, SQLITE3_TEXT);
            $cellResult = $this->selectQuery->execute();
            if ($cellResult === false) {
                throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
            }
            $cellData = $cellResult->fetchArray(SQLITE3_ASSOC);
            if ($cellData === false) {
                //    Return null if requested entry doesn't exist in cache
                return null;
            }
            //    Set current entry to the requested entry
            $this->currentObjectID = $pCoord;
            $this->currentObject = unserialize($cellData['value']);
            //    Re-attach this as the cell's parent
            $this->currentObject->attach($this);
            //    Return requested entry
            return $this->currentObject;
        }

        /**
         *    Is a value set for an indexed cell?
         * @param    string $pCoord Coordinate address of the cell to check
         * @return    boolean
         */
        public function isDataSet($pCoord) {
            if ($pCoord === $this->currentObjectID) {
                return true;
            }
            //    Check if the requested entry exists in the cache
            $this->selectQuery->bindValue('id', $pCoord, SQLITE3_TEXT);
            $cellResult = $this->selectQuery->execute();
            if ($cellResult === false) {
                throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
            }
            $cellData = $cellResult->fetchArray(SQLITE3_ASSOC);
            return ($cellData === false) ? false : true;
        }

        /**
         *    Delete a cell in cache identified by coordinate address
         * @param    string $pCoord Coordinate address of the cell to delete
         * @throws    PHPExcel_Exception
         */
        public function deleteCacheData($pCoord) {
            if ($pCoord === $this->currentObjectID) {
                $this->currentObject->detach();
                $this->currentObjectID = $this->currentObject = null;
            }
            //    Check if the requested entry exists in the cache
            $this->deleteQuery->bindValue('id', $pCoord, SQLITE3_TEXT);
            $result = $this->deleteQuery->execute();
            if ($result === false) {
                throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
            }
            $this->currentCellIsDirty = false;
        }

        /**
         * Move a cell object from one address to another
         * @param    string $fromAddress Current address of the cell to move
         * @param    string $toAddress   Destination address of the cell to move
         * @return    boolean
         */
        public function moveCell($fromAddress, $toAddress) {
            if ($fromAddress === $this->currentObjectID) {
                $this->currentObjectID = $toAddress;
            }
            $this->deleteQuery->bindValue('id', $toAddress, SQLITE3_TEXT);
            $result = $this->deleteQuery->execute();
            if ($result === false) {
                throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
            }
            $this->updateQuery->bindValue('toid', $toAddress, SQLITE3_TEXT);
            $this->updateQuery->bindValue('fromid', $fromAddress, SQLITE3_TEXT);
            $result = $this->updateQuery->execute();
            if ($result === false) {
                throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
            }
            return true;
        }

        /**
         * Get a list of all cell addresses currently held in cache
         * @return    string[]
         */
        public function getCellList() {
            if ($this->currentObjectID !== null) {
                $this->storeData();
            }
            $query         = "SELECT id FROM kvp_" . $this->TableName;
            $cellIdsResult = $this->DBHandle->query($query);
            if ($cellIdsResult === false) {
                throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
            }
            $cellKeys = [];
            while ($row = $cellIdsResult->fetchArray(SQLITE3_ASSOC)) {
                $cellKeys[] = $row['id'];
            }
            return $cellKeys;
        }

        /**
         * Clone the cell collection
         * @param    PHPExcel_Worksheet $parent The new worksheet
         * @return    void
         */
        public function copyCellCollection(PHPExcel_Worksheet $parent) {
            $this->currentCellIsDirty;
            $this->storeData();
            //    Get a new id for the new table name
            $tableName = str_replace('.', '_', $this->getUniqueID());
            if (!$this->DBHandle->exec('CREATE TABLE kvp_' . $tableName . ' (id VARCHAR(12) PRIMARY KEY, value BLOB)
            AS SELECT * FROM kvp_' . $this->TableName
            )
            ) {
                throw new PHPExcel_Exception($this->DBHandle->lastErrorMsg());
            }
            //    Copy the existing cell cache file
            $this->TableName = $tableName;
        }

        /**
         * Clear the cell collection and disconnect from our parent
         * @return    void
         */
        public function unsetWorksheetCells() {
            if (!is_null($this->currentObject)) {
                $this->currentObject->detach();
                $this->currentObject = $this->currentObjectID = null;
            }
            //    detach ourself from the worksheet, so that it can then delete this object successfully
            $this->parent = null;
            //    Close down the temporary cache file
            $this->__destruct();
        }

        /**
         * Destroy this cell collection
         */
        public function __destruct() {
            if (!is_null($this->DBHandle)) {
                $this->DBHandle->exec('DROP TABLE kvp_' . $this->TableName);
                $this->DBHandle->close();
            }
            $this->DBHandle = null;
        }
    }
